DjVuPort.h

//C- -*- C++ -*-//C- -------------------------------------------------------------------//C- DjVuLibre-3.5//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.//C- Copyright (c) 2001 AT&T//C-//C- This software is subject to, and may be distributed under, the//C- GNU General Public License, Version 2. The license should have//C- accompanied the software or you may obtain a copy of the license//C- from the Free Software Foundation at http://www.fsf.org .//C-//C- This program is distributed in the hope that it will be useful,//C- but WITHOUT ANY WARRANTY; without even the implied warranty of//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the//C- GNU General Public License for more details.//C- //C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library//C- distributed by Lizardtech Software. On July 19th 2002, Lizardtech //C- Software authorized us to replace the original DjVu(r) Reference //C- Library notice by the following text (see doc/lizard2002.djvu)://C-//C- ------------------------------------------------------------------//C- | DjVu (r) Reference Library (v. 3.5)//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.//C- | The DjVu Reference Library is protected by U.S. Pat. No.//C- | 6,058,214 and patents pending.//C- |//C- | This software is subject to, and may be distributed under, the//C- | GNU General Public License, Version 2. The license should have//C- | accompanied the software or you may obtain a copy of the license//C- | from the Free Software Foundation at http://www.fsf.org .//C- |//C- | The computer code originally released by LizardTech under this//C- | license and unmodified by other parties is deemed "the LIZARDTECH//C- | ORIGINAL CODE." Subject to any third party intellectual property//C- | claims, LizardTech grants recipient a worldwide, royalty-free, //C- | non-exclusive license to make, use, sell, or otherwise dispose of //C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the //C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU //C- | General Public License. This grant only confers the right to //C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to //C- | the extent such infringement is reasonably necessary to enable //C- | recipient to make, have made, practice, sell, or otherwise dispose //C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to //C- | any greater extent that may be necessary to utilize further //C- | modifications or combinations.//C- |//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.//C- +------------------------------------------------------------------// // $Id: DjVuPort.h,v 1.8 2003/11/07 22:08:21 leonb Exp $// $Name: debian_version_3_5_17-3 $#ifndef _DJVUPORT_H#define _DJVUPORT_H#ifdef HAVE_CONFIG_H#include "config.h"#endif#if NEED_GNUG_PRAGMAS# pragma interface#endif#include "GThreads.h"#include "GURL.h"#ifdef HAVE_NAMESPACESnamespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode}
#endif#endifclass DataPool;
/** @name DjVuPort.h Files #"DjVuPort.h"# and #"DjVuPort.cpp"# implement a communication mechanism between different parties involved in decoding DjVu files. It should be pretty clear that the creator of \Ref{DjVuDocument} and \Ref{DjVuFile} would like to receive some information about the progress of decoding, errors occurred, etc. It may also want to provide source data for decoders (like it's done in the plugin where the real data is downloaded from the net and is fed into DjVu decoders). Normally this functionality is implemented by means of callbacks which are run when a given condition comes true. Unfortunately it's not quite easy to implement this strategy in our case. The reason is that there may be more than one "client" working with the same document, and the document should send the information to each of the clients. This could be done by means of callback {\em lists}, of course, but we want to achieve more bulletproof results: we want to be sure that the client that we're about to contact is still alive, and is not being destroyed by another thread. Besides, we are going to call these "callbacks" from many places, from many different classes. Maintaining multi-thread safe callback lists is very difficult. Finally, we want to provide some default implementation of these "callbacks" in the library, which should attempt to process the requests themselves if they can, and contact the client only if they're unable to do it (like in the case of \Ref{DjVuPort::request_data}() with local URL where \Ref{DjVuDocument} can get the data from the hard drive itself not disturbing the document's creator. Two classes implement a general communication mechanism: \Ref{DjVuPort} and \Ref{DjVuPortcaster}. Any sender and recipient of requests should be a subclass of \Ref{DjVuPort}. \Ref{DjVuPortcaster} maintains a map of routes between \Ref{DjVuPort}s, which should be configured by somebody else. Whenever a port wants to send a request, it calls the corresponding function of \Ref{DjVuPortcaster}, and the portcaster relays the request to all the destinations that it sees in the internal map. The \Ref{DjVuPortcaster} is responsible for keeping the map up to date by getting rid of destinations that have been destroyed. Map updates are performed from a single place and are serialized by a global monitor. @memo DjVu decoder communication mechanism. @author Andrei Erofeev <eaf@geocities.com>\\ L\'eon Bottou <leonb@research.att.com> @version #$Id: DjVuPort.h,v 1.8 2003/11/07 22:08:21 leonb Exp $# *///@{class DjVuPort;
class DjVuPortcaster;
class DjVuFile;
/** Base class for notification targets. #DjVuPort# provides base functionality for classes willing to take part in sending and receiving messages generated during decoding process. You need to derive your class from #DjVuPort# if you want it to be able to send or receive requests. In addition, for receiving requests you should override one or more virtual function. {\bf Important remark} --- All ports should be allocated on the heap using #operator new# and immediately secured using a \Ref{GP} smart pointer. Ports which are not secured by a smart-pointer are not considered ``alive'' and never receive notifications! */00141class DjVuPort : publicGPEnabled
{
public:
DjVuPort();
virtual ~DjVuPort();
staticvoid *operator new (size_t sz);
staticvoid operator delete(void *addr);
/** Use this function to get a copy of the global \Ref{DjVuPortcaster}. */staticDjVuPortcaster *get_portcaster(void);
/** Copy constructor. When #DjVuPort#s are copied, the portcaster copies all incoming and outgoing routes of the original. */DjVuPort(constDjVuPort & port);
/** Copy operator. Similarly to the copy constructor, the portcaster copies all incoming and outgoing coming routes of the original. */DjVuPort & operator=(constDjVuPort & port);
/** Should return 1 if the called class inherits class #class_name#. When a destination receives a request, it can retrieve the pointer to the source #DjVuPort#. This virtual function should be able to help to identify the source of the request. For example, \Ref{DjVuFile} is also derived from #DjVuPort#. In order for the receiver to recognize the sender, the \Ref{DjVuFile} should override this function to return #TRUE# when the #class_name# is either #DjVuPort# or #DjVuFile# */virtualboolinherits(constGUTF8String &class_name) const;
/** @name Notifications. These virtual functions may be overridden by the subclasses of #DjVuPort#. They are called by the \Ref{DjVuPortcaster} when the port is alive and when there is a route between the source of the notification and this port. */ //@{ /** This request is issued to request translation of the ID, used in an DjVu INCL chunk to a URL, which may be used to request data associated with included file. \Ref{DjVuDocument} usually intercepts all such requests, and the user doesn't have to worry about the translation */virtualGURLid_to_url(constDjVuPort * source, constGUTF8String &id);
/** This request is used to get a file corresponding to the given ID. \Ref{DjVuDocument} is supposed to intercept it and either create a new instance of \Ref{DjVuFile} or reuse an existing one from the cache. */virtualGP<DjVuFile>id_to_file(constDjVuPort * source, constGUTF8String &id);
/** This request is issued when decoder needs additional data for decoding. Both \Ref{DjVuFile} and \Ref{DjVuDocument} are initialized with a URL, not the document data. As soon as they need the data, they call this function, whose responsibility is to locate the source of the data basing on the #URL# passed and return it back in the form of the \Ref{DataPool}. If this particular receiver is unable to fullfil the request, it should return #0#. */virtualGP<DataPool>request_data(constDjVuPort * source, constGURL & url);
/** This notification is sent when an error occurs and the error message should be shown to the user. The receiver should return #0# if it is unable to process the request. Otherwise the receiver should return 1. */virtualboolnotify_error(constDjVuPort * source, constGUTF8String &msg);
/** This notification is sent to update the decoding status. The receiver should return #0# if it is unable to process the request. Otherwise the receiver should return 1. */virtualboolnotify_status(constDjVuPort * source, constGUTF8String &msg);
/** This notification is sent by \Ref{DjVuImage} when it should be redrawn. It may be used to implement progressive redisplay. @param source The sender of the request */virtualvoidnotify_redisplay(constclassDjVuImage * source);
/** This notification is sent by \ref{DjVuImage} when its geometry has been changed as a result of decoding. It may be used to implement progressive redisplay. */virtualvoidnotify_relayout(constclassDjVuImage * source);
/** This notification is sent when a new chunk has been decoded. */virtualvoidnotify_chunk_done(constDjVuPort * source, constGUTF8String &name);
/** This notification is sent after the \Ref{DjVuFile} flags have been changed. This happens, for example, when: \begin{itemize} \item Decoding succeeded, failed or just stopped \item All data has been received \item All included files have been created \end{itemize} @param source \Ref{DjVuFile}, which flags have been changed @param set_mask bits, which have been set @param clr_mask bits, which have been cleared */virtualvoidnotify_file_flags_changed(constclassDjVuFile * source,
long set_mask, long clr_mask);
/** This notification is sent after the \Ref{DjVuDocument} flags have been changed. This happens, for example, after it receives enough data and can determine its structure (#BUNDLED#, #OLD_INDEXED#, etc.). @param source \Ref{DjVuDocument}, which flags have been changed @param set_mask bits, which have been set @param clr_mask bits, which have been cleared */virtualvoidnotify_doc_flags_changed(constclassDjVuDocument * source,
long set_mask, long clr_mask);
/** This notification is sent from time to time while decoding is in progress. The purpose is obvious: to provide a way to know how much is done and how long the decoding will continue. Argument #done# is a number from 0 to 1 reflecting the progress. */virtualvoidnotify_decode_progress(constDjVuPort * source, float done);
/** This is the standard types for defining what to do in case of errors. This is only used by some of the subclasses, but it needs to be defined here to guarantee all subclasses use the same enum types. In general, many errors are non recoverable. Using a setting other than ABORT may just result in even more errors. */00259enumErrorRecoveryAction {ABORT=0,SKIP_PAGES=1,SKIP_CHUNKS=2,KEEP_ALL=3 }; //@}public:
class DjVuPortCorpse;
private:
static GCriticalSection * corpse_lock;
static DjVuPortCorpse * corpse_head, * corpse_tail;
staticint corpse_num;
};
/** Simple port. An instance of #DjVuSimplePort# is automatically created when you create a \Ref{DjVuFile} or a \Ref{DjVuDocument} without specifying a port. This simple port can retrieve data for local urls (i.e. urls referring to local files) and display error messages on #stderr#. All other notifications are ignored. */00276class DjVuSimplePort : publicDjVuPort
{
public: /// Returns 1 if #class_name# is #"DjVuPort"# or #"DjVuSimplePort"#.virtualboolinherits(constGUTF8String &class_name) const;
/** If #url# is local, it created a \Ref{DataPool}, connects it to the file with the given name and returns. Otherwise returns #0#. */virtualGP<DataPool>request_data(constDjVuPort * source, constGURL & url);
/// Displays error on #stderr#. Always returns 1.virtualboolnotify_error(constDjVuPort * source, constGUTF8String &msg);
/// Displays status on #stderr#. Always returns 1.virtualboolnotify_status(constDjVuPort * source, constGUTF8String &msg);
};
/** Memory based port. This \Ref{DjVuPort} maintains a map associating pseudo urls with data segments. It processes the #request_data# notifications according to this map. After initializing the port, you should add as many pairs #<url, pool># as needed need and add a route from a \Ref{DjVuDocument} or \Ref{DjVuFile} to this port. */00301class DjVuMemoryPort : publicDjVuPort
{
public: /// Returns 1 if #class_name# is #"DjVuPort"# or #"DjVuMemoryPort"#virtualboolinherits(constGUTF8String &class_name) const;
/** If #url# is one of those, that have been added before by means of \Ref{add_data}() function, it will return the associated \Ref{DataPool}. #ZERO# otherwize. */virtualGP<DataPool>request_data(constDjVuPort * source, constGURL & url);
/** Adds #<url, pool># pair to the internal map. From now on, if somebody asks for data corresponding to the #url#, it will be returning the #pool# */voidadd_data(constGURL & url, constGP<DataPool> & pool);
private:
GCriticalSection lock;
GPMap<GURL, DataPool>map;
};
/** Maintains associations between ports. It monitors the status of all ports (have they been destructed yet?), accepts requests and notifications from them and forwards them to destinations according to internally maintained map of routes. The caller can modify the route map any way he likes (see \Ref{add_route}(), \Ref{del_route}(), \Ref{copy_routes}(), etc. functions). Any port can be either a sender of a message, an intermediary receiver or a final destination. When a request is sent, the #DjVuPortcaster# computes the list of destinations by consulting with the route map. Notifications are only sent to ``alive'' ports. A port is alive if it is referenced by a valid \Ref{GP} smartpointer. As a consequence, a port usually becomes alive after running the constructor (since the returned pointer is then assigned to a smartpointer) and is no longer alive when the port is destroyed (because it would not be destroyed if a smartpointer was referencing it). Destination ports are sorted according to their distance from the source. For example, if port {\bf A} is connected to ports {\bf B} and {\bf C} directly, and port {\bf B} is connected to {\bf D}, then {\bf B} and {\bf C} are assumed to be one hop away from {\bf A}, while {\bf D} is two hops away from {\bf A}. In some cases the requests and notifications are sent to every possible destination, and the order is not significant (like it is for \Ref{notify_file_flags_changed}() request). Others should be sent to the closest destinations first, and only then to the farthest, in case if they have not been processed by the closest. The examples are \Ref{request_data}(), \Ref{notify_error}() and \Ref{notify_status}(). The user is not expected to create the #DjVuPortcaster# itself. He should use \Ref{get_portcaster}() global function instead. */00356class DjVuPortcaster
{
public: /** Use this function to get a copy of the global \Ref{DjVuPortcaster}. */00360staticDjVuPortcaster *get_portcaster(void)
{ returnDjVuPort::get_portcaster(); } ;
/** The default constructor. */DjVuPortcaster(void);
virtual ~DjVuPortcaster(void);
/** Removes the specified port from all routes. It will no longer be able to receive or generate messages and will be considered {\bf "dead"} by \Ref{is_port_alive}() function. */voiddel_port(constDjVuPort * port);
/** Adds route from #src# to #dst#. Whenever a request is sent or received by #src#, it will be forwarded to #dst# as well. @param src The source @param dst The destination */voidadd_route(constDjVuPort *src, DjVuPort *dst);
/** The opposite of \Ref{add_route}(). Removes the association between #src# and #dst# */voiddel_route(constDjVuPort *src, DjVuPort *dst);
/** Copies all incoming and outgoing routes from #src# to #dst#. This function should be called when a \Ref{DjVuPort} is copied, if you want to preserve the connectivity. */voidcopy_routes(DjVuPort *dst, constDjVuPort *src);
/** Returns a smart pointer to the port if #port# is a valid pointer to an existing #DjVuPort#. Returns a null pointer otherwise. */GP<DjVuPort>is_port_alive(DjVuPort *port);
/** Assigns one more {\em alias} for the specified \Ref{DjVuPort}. {\em Aliases} are names, which can be used later to retrieve this \Ref{DjVuPort}, if it still exists. Any \Ref{DjVuPort} may have more than one {\em alias}. But every {\em alias} must correspond to only one \Ref{DjVuPort}. Thus, if the specified alias is already associated with another port, this association will be removed. */voidadd_alias(constDjVuPort * port, constGUTF8String &alias);
/** Removes all the aliases */staticvoidclear_all_aliases(void);
/** Removes all aliases associated with the given \Ref{DjVuPort}. */voidclear_aliases(constDjVuPort * port);
/** Returns \Ref{DjVuPort} associated with the given #alias#. If nothing is known about name #alias#, or the port associated with it has already been destroyed #ZERO# pointer will be returned. */GP<DjVuPort>alias_to_port(constGUTF8String &name);
/** Returns a list of \Ref{DjVuPort}s with aliases starting with #prefix#. If no \Ref{DjVuPort}s have been found, empty list is returned. */GPList<DjVuPort>prefix_to_ports(constGUTF8String &prefix);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest until one of them returns non-empty \Ref{GURL}. */virtualGURLid_to_url(constDjVuPort * source, constGUTF8String &id);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest until one of them returns non-zero pointer to \Ref{DjVuFile}. */virtualGP<DjVuFile>id_to_file(constDjVuPort * source, constGUTF8String &id);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest until one of them returns non-zero \Ref{DataPool}. */virtualGP<DataPool>request_data(constDjVuPort * source, constGURL & url);
/** Computes destination list for #source# and calls the corresponding. function in each of the ports from the destination starting from the closest until one of them returns 1. */virtualboolnotify_error(constDjVuPort * source, constGUTF8String &msg);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest until one of them returns 1. */virtualboolnotify_status(constDjVuPort * source, constGUTF8String &msg);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_redisplay(constclassDjVuImage * source);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_relayout(constclassDjVuImage * source);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_chunk_done(constDjVuPort * source, constGUTF8String &name);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_file_flags_changed(constclassDjVuFile * source,
long set_mask, long clr_mask);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_doc_flags_changed(constclassDjVuDocument * source,
long set_mask, long clr_mask);
/** Computes destination list for #source# and calls the corresponding function in each of the ports from the destination list starting from the closest. */virtualvoidnotify_decode_progress(constDjVuPort * source, float done);
private:
// We use these 'void *' to minimize template instantiations.friendclass DjVuPort;
GCriticalSection map_lock;
GMap<const void *, void *> route_map; // GMap<DjVuPort *, GList<DjVuPort *> *>GMap<const void *, void *> cont_map; // GMap<DjVuPort *, DjVuPort *>GMap<GUTF8String, const void *> a2p_map; // GMap<GUTF8String, DjVuPort *>void add_to_closure(GMap<const void*, void*> & set,
constDjVuPort *dst, int distance);
void compute_closure(constDjVuPort *src, GPList<DjVuPort> &list,
bool sorted=false);
};
inlinebool00490DjVuPort::inherits(constGUTF8String &class_name) const{
return (class_name == "DjVuPort");
}
inlinebool00496DjVuSimplePort::inherits(constGUTF8String &class_name) const{
return
(class_name == "DjVuSimplePort") || DjVuPort::inherits(class_name);
}
inlinebool00503DjVuMemoryPort::inherits(constGUTF8String &class_name) const{
return
(class_name == "DjVuMemoryPort") || DjVuPort::inherits(class_name);
}
//@}#ifdef HAVE_NAMESPACES}
# ifndef NOT_USING_DJVU_NAMESPACEusing namespace DJVU;
# endif#endif#endif